FDSOI process technology includes a continuous buried oxide (BOX) layer common to all devices on a wafer. One of the core benefits of FDSOI is the ability to control threshold voltage (Vt) by controlling backside voltages. However, an IC device may include different devices, e.g., an input/output (I/O) device, etc., formed on the same wafer, which have different trade-offs for channel control, subthreshold slope, and operating voltage. The device tradeoffs are typically set by adjustments to the gate oxide and threshold implants, but on FDSOI, this is also possible through bias to the backgate.
It would therefore be advantageous to have a methodology enabling formation of multiple devices with different Vts on a wafer with better channel control and the resulting device.